Belactins A and B, New Serine Carboxy-Peptidase Inhibitors Produced by Actinomycete. II. Physico-Chemical Properties, Structure Determinations and Enzymatic Inhibitory Activities Compared with other ß-Lactone Containing Inhibitors

Abstract

Belactins A and B, new inhibitors of serine carboxypeptidase were discovered in the fermentation broth of Saccharopolyspora sp. MK19-42F6. The structures of belactins A and B were determined to be 4-[3-[(2-amino-5-chlorobenzoyl)amino]-1,1-dimethyl-2-oxobutyl]-3- methyl-2-oxetanone and 4-[3-[[2-(beta-glucopyranosylamino)-5-chlorobenzoyl]amino]-1,1- dimethyl-2-oxobutyl]-3-methyl-2-oxetanone respectively by various spectral analyses. Belactins A and B do not inhibit esterase or lipase at 100 micrograms/ml but have more specific inhibitory activities towards carboxypeptidase Y (CP-Y) compared with other beta-lactone-containing inhibitors, such as ebelactones A, B and esterastin.